U.S. patent application number 10/574621 was filed with the patent office on 2007-03-08 for force-sensing device.
Invention is credited to Jurgen Herhaus.
Application Number | 20070051190 10/574621 |
Document ID | / |
Family ID | 34428251 |
Filed Date | 2007-03-08 |
United States Patent
Application |
20070051190 |
Kind Code |
A1 |
Herhaus; Jurgen |
March 8, 2007 |
Force-sensing device
Abstract
A force-sensing device has a yoke having a location of force
introduction for a force to be measured acting in a predetermined
direction. A measuring spring has a first end rigidly connected to
the yoke and is elastically deformable by the force to be measured.
The measuring spring has a second end arranged on a support rigidly
connectable to a machine frame. First predetermined measuring
locations are provided that detect and evaluate a deformation of
the measuring spring caused by the force to be measured. Parallel
and spaced apart bending springs are connected to the yoke in such
a way that the yoke is always guided in parallel in a transverse
direction that is transverse to the predetermined direction of the
force to be measured. Second predetermined measuring locations are
provided on the bending springs and detect a transverse deformation
caused by a force in the transverse direction.
Inventors: |
Herhaus; Jurgen;
(Radevormwald, DE) |
Correspondence
Address: |
GUDRUN E. HUCKETT DRAUDT
LONSSTR. 53
WUPPERTAL
42289
DE
|
Family ID: |
34428251 |
Appl. No.: |
10/574621 |
Filed: |
October 6, 2004 |
PCT Filed: |
October 6, 2004 |
PCT NO: |
PCT/EP04/11162 |
371 Date: |
April 5, 2006 |
Current U.S.
Class: |
73/862.636 |
Current CPC
Class: |
G01L 1/2243
20130101 |
Class at
Publication: |
073/862.636 |
International
Class: |
G01L 1/04 20060101
G01L001/04 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 6, 2003 |
DE |
10346811.0 |
Claims
1-18. (canceled)
19. A force-sensing device comprising: a yoke having a location of
force introduction for a force to be measured acting in a
predetermined direction on the location of force introduction; at
least one measuring spring having a first end rigidly connected to
the yoke and elastically deformable by the force to be measured
acting on the location of force introduction; a support adapted to
be rigidly connected to a machine frame; the at least one measuring
spring having a second end arranged on the support; first
predetermined measuring locations that detect and evaluate a
deformation of the at least one measuring spring caused by the
force to be measured; at least two bending springs that are
parallel relative to one another and spaced apart from one another
and are connected to the yoke in such a way that the yoke is always
guided in parallel in a transverse direction that is transverse to
the predetermined direction of the force to be measured; and second
predetermined measuring locations provided for the at least two
bending springs, the second measuring locations detecting a
transverse deformation caused by a force in the transverse
direction.
20. The force-sensing device according to claim 19, wherein the at
least two bending springs extend between the yoke and the
support.
21. The force-sensing device according to claim 19, wherein the at
least two bending springs have a section modulus in the transverse
direction that surpasses a section modulus of the at least one
measuring spring in the predetermined direction of the force to be
measured.
22. The force-sensing device according to claim 19, wherein the
transverse direction is positioned perpendicularly to the
predetermined direction of the force to be measured.
23. The force-sensing device according to claim 19, wherein the at
least one measuring spring has a slot extending in a longitudinal
direction of the at least one measuring spring, wherein a slot
plane of the slot is perpendicular to the transverse direction.
24. The force-sensing device according to claim 19, wherein the
yoke has an annular receiving zone for a rolling bearing.
25. The force-sensing device according to claim 19, further
comprising a mandrel connectable rigidly to the machine frame,
wherein the support is annular and the mandrel penetrates the
support, wherein the mandrel has a head and is connected by the
head to an outer end of the support.
26. The force-sensing device according to claim 25, wherein the
mandrel is securable infinitely variably in a range of 360 degrees
in any of many different rotational positions on the machine
frame.
27. The force-sensing device according to claim 26, further
comprising a clamping socket adapted to be connected to the machine
frame and having a fitted bore and a clamp bore intercepting the
fitted bore, the clamping socket further having a pair of clamping
jaws arranged in the clamp bore, wherein a free end of the mandrel
is mounted in the fitted bore of the clamping socket and wherein
the clamping jaws engage two sides of the mandrel.
28. The force-sensing device according to claim 27, wherein the
clamping jaws are penetrated by a clamping screw positioned outside
of the fitted bore.
29. The force-sensing device according to claim 28, wherein the
clamping screw has a shaft mounted in a through bore of a first one
of the clamping jaws and wherein a second one of the clamping jaws
has a threaded bore receiving the clamping screw.
30. The force-sensing device according to claim 25, further
comprising an extension axle having a first counter flange, wherein
the head of the mandrel has a screwed-on flange to which is
connected the first counter flange of the extension axle.
31. The force-sensing device according to claim 30, wherein the
extension axle has a second counter flange remote from the first
counter flange, wherein an additional force-sensing device
according to claim 19 is mirror-symmetrically attached to the
second counter flange.
32. The force-sensing device according to claim 31, wherein the
mandrel in a longitudinal area of the at least one measuring spring
has a cable inlet opening that is intercepted by a longitudinal
bore of the mandrel, wherein the longitudinal bore of the mandrel
extends at least to one end of the mandrel and opens at the end of
the mandrel.
33. The force-sensing device according to claim 32, wherein the
extension axle across an entire length of the extension axle is
penetrated by an axle bore that is aligned with the longitudinal
bore of the mandrel.
34. The force-sensing device according to claim 25, wherein the
mandrel has a key engaging surface that is preferably
concentrically positioned relative to a longitudinal axis of the
mandrel.
35. The force-sensing device according to claim 19, wherein two of
the at least one measuring spring are arranged parallel to one
another and spaced apart from one another, wherein the first ends
of said two measuring springs are non-pivotably connected to one
another by the yoke and wherein the second ends are rigidly
connected with the machine frame.
36. The force-sensing device according to claim 35, further
comprising a shearing force sensor arranged between said two
measuring springs, wherein a deformation of the shearing force
sensor is detected on a surface of the shearing force sensor in a
plane parallel to the predetermined direction of the force to be
measured and evaluated.
37. A force-sensing device comprising: a yoke having a location of
force introduction for a force to be measured acting in a
predetermined direction on the location of force introduction; at
least one measuring spring having a first end rigidly connected to
the yoke and elastically deformable by the force to be measured
acting on the location of force introduction; a support adapted to
be rigidly connected to a machine frame; the at least one measuring
spring having a second end arranged on the support; first
predetermined measuring locations that detect and evaluate a
deformation of the at least one measuring spring caused by the
force to be measured; the support having an annular shape; a
mandrel penetrating the support and adapted to be rigidly connected
to the machine frame; the mandrel having a head and connected by
the head to an outer end of the support.
38. The force-sensing device according to claim 37, wherein the
mandrel is securable infinitely variably in a range of 360 degrees
in any of many different rotational positions on the machine
frame.
39. The force-sensing device according to claim 38, further
comprising a clamping socket adapted to be connected to the machine
frame and having a fitted bore and a clamp bore intercepting the
fitted bore, the clamping socket further having a pair of clamping
jaws arranged in the clamp bore, wherein a free end of the mandrel
is mounted in the fitted bore of the clamping socket and wherein
the clamping jaws engage two sides of the mandrel.
40. The force-sensing device according to claim 39, wherein the
clamping jaws are penetrated by a clamping screw positioned outside
of the fitted bore.
41. The force-sensing device according to claim 40, wherein the
clamping screw has a shaft mounted in a through bore of a first one
of the clamping jaws and wherein a second one of the clamping jaws
has a threaded bore receiving the clamping screw.
42. The force-sensing device according to claim 37, further
comprising an extension axle having a counter flange, wherein the
head of the mandrel has a screwed-on flange to which is connected
the counter flange of the extension axle.
Description
[0001] The present invention relates to a force-sensing device
according to the preamble of the independent claim.
[0002] Such force-sensing device is disclosed in EP 0 621 469 B1.
This force-sensing device has a special feature in that, for
measuring a force expected to act in a predetermined direction, a
pair of measuring springs are provided that are parallel to one
another and spaced apart from one another. This arrangement is
referred to as a "double bending beam"; however, in connection with
the present invention this is not to be understood as a limitation
to such arrangements of measuring springs. Therefore, for measuring
such forces, all conceivable measuring spring arrangements are
taken into consideration, i.e., also single bending beams, shearing
force sensors, torsion sensors etc.
[0003] An important feature of this known force-sensing
device--without being limited to it--is the arrangement of two
parallel measuring springs that are connected with one end to a
support that is to be connected rigidly to the machine frame. The
other ends of the measuring springs are connected to one another by
means of a yoke. By means of the yoke, the force to be measured is
introduced into the system.
[0004] With this arrangement of support, measuring springs, and
yoke, the yoke is displaced always parallel to itself when loaded.
Such force-sensing devices have significant advantages with regard
to stiffness and reproducible signal generation. In particular,
they are able to detect high nominal loads even for minimal
deflections.
[0005] Of course, this does not apply in the case of other possible
measuring arrangements (single bending arrangement, shearing force
sensor, torsion sensor etc.); however, they are suitable for the
present invention as well.
[0006] When the yoke is moreover provided with a rolling bearing
seat, it is possible to very well manufacture with such a
force-sensing device also so-called measuring rollers that are
characterized in particular in that also the rolling bearing is
always displaced parallel to itself under load.
[0007] It is therefore an object of the present invention to
configure the known force-sensing device in such a way that, while
maintaining the aforementioned known advantages of measuring
springs of different designs, a high stiffness can be achieved even
for load directions that are outside of the predetermined direction
in which the force to be measured acts.
[0008] This object is solved by the invention with the features of
the independent claim.
[0009] The invention provides the advantage that, in comparison to
the stiffness values of known force-sensing devices, a stiffness
that is four times greater can be obtained for transversely
positioned force directions and comparable cross-sectional
dimensions. This increase of stiffness therefore follows the
requirement of achieving in the transverse direction only minimal
deflections so that a high lateral load resistance is obtained.
[0010] In this connection, the ability to take up high lateral
loads is not paired with surrendering anything for obtaining high
nominal measuring loads.
[0011] This advantage is achieved in that in the transverse
direction two bending springs that are parallel to one another and
spaced apart from one another are provided that deform under a load
in the transverse direction in the same way as the double bending
beam provided--in the case of the known force-sensing device--for
the measuring direction.
[0012] Since each of the transversely positioned bending springs is
deformed to an shape under the transverse load and therefore has a
bending line with two turning points, the force-sensing device
according to the invention therefore counteracts the transverse
force with a correspondingly high resistance that leads precisely
to the comparatively minimal deflections despite correspondingly
high transverse forces.
[0013] In this connection, even under the effect of the transverse
load, the yoke that bends the bending springs is always displaced
parallel to itself so that the force-sensing device is moreover
excellently suitable for a combination with rolling bearings that
can be arranged on appropriate rolling bearing seats of the
yoke.
[0014] The exact parallel movement of the rolling bearings is, for
example, required for measuring tasks on rollers when a
displacement of the measuring roller that is free of secondary
bending moment is an important factor. In such cases, it must be
ensured that under the effect of transverse forces the strip edges
of the strip do not deviate from the predetermined path as a result
of an undesirable displacement of the measuring roller.
[0015] The features of claim 2 lead to a compact configuration. For
this purpose, it is provided that those bending springs that are
provided for taking up the transverse forces extend between the
support and the yoke like the at least one measuring spring that is
provided for detecting the force-caused deformation.
[0016] The additional bending springs can therefore be connected as
monolithic parts of the yoke and the support.
[0017] Especially advantageous, however, is a further embodiment in
which the transversely positioned bending springs are machined by
means of appropriate measurers out of the measuring spring or
springs serving for detecting the force to be measured.
[0018] Even though this is basically not to be understood as a
limitation of the invention, it is expressly stated that the
bending springs can also serve for qualitative detection of the
transverse forces or, depending on the mounting situation, can also
serve "simply" for providing geometric parallel guiding of the yoke
under the effect of a transverse force. In any case, the stiffness
values of the bending springs can be manufactured in a defined way
for every measuring task without having to give up the advantages
of the double bending beam that is known in special configuration
in the prior art and that is provided, only in the direction of the
force to be measured, with two or even more parallel bending
springs to be deformed to an S-shape.
[0019] For this purpose, it can also be expedient to select the
section modulus of the bending springs in that direction that
coincides with the transverse direction to be significantly higher
than the section modulus of the measuring springs provided for
force measurement. Such a force-sensing device would therefore be
significantly stiffer in the transverse direction than in the
measuring direction.
[0020] This measure can be expedient, for example, in so-called
measuring rollers that are subjected to a significant dead load but
in the measuring direction must take up only minimal nominal
measuring forces for material and/or process technological
reasons.
[0021] The position of the transverse direction relative to the
direction of the predetermined force is essentially random as long
as the transverse direction and predetermined force have an angle
between them that is greater than 0 degrees (except 180
degrees).
[0022] For most applications, it should however be sufficient to
configure the force-sensing device for transverse directions that
are perpendicular to the direction of the force to be measured.
[0023] Especially advantageous is a further embodiment in which the
measuring spring or springs provided for force measurement is/are
provided with slots that extend on the one hand in the longitudinal
direction of the measuring springs and on the other hand are
positioned with their slot plane perpendicularly to the transverse
direction.
[0024] In this way, the known measuring springs provided for force
measurement are also used for generating the additional bending
springs so that by means of the essentially known manufacturing
technology of such force-sensing devices additionally also a high
lateral load stiffness can be achieved.
[0025] A further embodiment of the invention provides a projecting
support action on a machine frame.
[0026] For this purpose, it is proposed to configure the support to
be of an annular shape and to secure the support by means of a
mandrel on the machine frame which mandrel penetrates the annular
recess of the support, wherein the mandrel has a head on the side
facing away from the machine frame which head is connected to the
outer side of the support.
[0027] This embodiment has particularly the advantage that the
mandrel can be secured on the machine frame in random different
rotational positions within an angular range of 360 degrees.
[0028] Advantageously, the mandrel is secured in a clamping socket
that can be connected rigidly to the machine frame. This clamping
socket has a fitted bore for the mandrel which is intercepted by a
clamp bore. In the clamp bore a clamping jaw pair is arranged and
engages two sides of the mandrel. This is achieved in that one
clamping jaw is arranged on one side of the fitted bore and the
other clamping jaw is arranged on the other side of the fitted
bore.
[0029] As a result of the paired interaction between the clamping
jaws, during the clamping process a relative rotation of the
mandrel in the fitted bore is prevented. The clamping forces acting
on the mandrel in the circumferential direction, respectively,
compensate one another.
[0030] An advantageous further embodiment provides that the
clamping jaw pair is to be actuated by a clamping screw whose shaft
is seated in a through bore of one clamping jaw while the other
clamping jaw has a threaded bore that matches the thread of the
clamping screw.
[0031] This embodiment of the invention has the advantage that the
clamping screw can extend completely within the clamping socket and
is thus recessed within the envelope of the clamping socket.
[0032] The force-sensing device according to the present invention
enables in particular also a modular configuration.
[0033] In this connection, it is additionally proposed that a
counter flange of an extension axle can be mounted externally on
the head of the mandrel by means of a screwed-on flange provided
thereat.
[0034] At the end of the extension axle a further counter flange
can be provided which serves for receiving a mirror-symmetrically
arranged force-sensing device.
[0035] Since particularly the further embodiment according to claim
7 can be designed independent of the pair of parallel bending
springs, the possibility of a modular configuration of the entire
force-sensing device provides also the advantage of manufacturing
so-called measuring rollers; such measuring rollers are either not
under the effect of transverse forces or the transverse forces have
no effect on such measuring rollers.
[0036] Since particularly such measuring rollers with a single side
support action are under the effect of their dead load, both
configurations of the invention can be advantageous, depending on
whether the transverse force is significant and/or must be taken
into account.
[0037] In this connection, the cable placement is also of
significant importance.
[0038] In this connection, it is expedient to provide the mandrel
in the longitudinal area of the bending springs with a cable inlet
opening that is intercepted by a longitudinal bore of the
mandrel.
[0039] By means of these communicating bores, the cables can be
guided out of the force-sensing device to the machine frame.
[0040] In the case of a measuring roller, the extension axle should
also be hollow so that the measuring cable can be guided outwardly
via this axle bore to the machine frame.
[0041] For a precise alignment of the force-sensing device in such
a way that the measuring axis of the bending springs designed for
force measurement coincides with the line of action of the force to
be measured, it is proposed additionally that the mandrel has a key
engaging surface that is preferably concentric to the mandrel
axis.
[0042] In the following the invention will be explained with the
aid of embodiments in more detail.
[0043] It is shown in:
[0044] FIG. 1 a first embodiment of the invention;
[0045] FIG. 2 an embodiment of the invention on a measuring
roller;
[0046] FIG. 3 a section view along the line III-III of FIG. 2;
[0047] FIG. 4 details for placing the measuring cables;
[0048] FIG. 5 a further embodiment of the invention;
[0049] FIG. 6 the embodiment according to FIG. 5 in a side
view;
[0050] FIG. 7 the embodiment according to FIG. 5 in a top view.
[0051] If nothing else is mentioned, the following description
always applies to all Figures.
[0052] The Figures show a force-sensing device 1 for measuring a
force 2. The force 2 acts in a predetermined direction 3 on the
location of force introduction 4 of the force-sensing device 1.
[0053] The location of force introduction 4 is connected by a yoke
5 to the free ends 8 of--in this embodiment--two parallel measuring
springs 6, 7, which ends point in the same direction. A single or
more than two parallel measuring springs can be provided also. The
measuring springs 6, 7 are provided for force measurement. The
connection between measuring springs 6, 7 and yoke 5 is designed as
a rigid connection. The other end 9 of the measuring springs 6, 7
is positioned on a support 10 that can be rigidly connected to the
machine frame 50. The force-caused deformation of the bending
springs 6, 7, i.e., the deformation caused by the force 2 to be
measured, is detected at predetermined measuring locations 11a-11d
and evaluated. The detection is expediently realized by means of
wire strain gauges. When four identical wire strain gauges are
used, a measuring circuit in the form of a Wheatstone bridge is
expedient.
[0054] The difference between the embodiments of the FIGS. 1 to 4
and the FIGS. 5 to 8 resides in that in the case of the FIGS. 1 to
4 the measuring springs 6, 7 are always configured as so-called
pure double bending beams.
[0055] This refers to two bending beams that are parallel to one
another and spaced apart from one another and with one end are
connected by the yoke 5 non-pivotally and with their other end 9
are rigidly connected to the machine frame 50.
[0056] In the case of the so-called double bending beam, there is
no material between the two measuring springs so that these two
measuring springs 6, 7 when the yoke 5 is loaded are always
deformed to an S-shape with identical spacing relative to one
another. The bending line itself has always two turning points
where the curvature changes from right to left or from left to
right.
[0057] In contrast to this, FIGS. 5 to 7 show a different
embodiment.
[0058] The measuring springs 6, 7 are connected by a so-called
shearing force sensor 6' at their common longitudinal center
plane.
[0059] The shearing force sensor 6' is formed by a bore introduced
into the force sensing device 1 on both sides that creates a kind
of elastically deformable diaphragm because the bores on either
side do not completely penetrate the force-sensing device 1.
[0060] In this way, there are also two parallel measuring springs
6, 7; however, they can no longer be referred to as double bending
beam.
[0061] The bending line of these measuring springs 6, 7 is shown in
FIG. 6 at the bottom.
[0062] The bending line has a qualitative extension with, in
principle, two turning points.
[0063] However, it does not correspond to the course of a double
bending beam because superposition effects, as in the case of a
single bending beam, are unavoidable by means of the centrally
arranged shearing force sensor.
[0064] Depending on the depth of the introduced bore shown in FIG.
5, such a bending line will approximate more and more the bending
line of a single bending beam with decreasing depth.
[0065] Even though, such a configuration is of course suitable for
the purposes of the invention.
[0066] It is important in this context that the yoke 5 is guided in
parallel by means of at least one (additional) pair of bending
springs 12, 13, 14 that are parallel to one another in a transverse
direction 15 that is perpendicular to the direction 3 of the
predetermined force 2.
[0067] In this connection, it should be noted that as a result of
the measuring springs 6, 7 that represent together a double bending
beam the yoke is already parallel-guided in that direction that
leads to a displacement of the yoke 5 as a result of the force 2 to
be measured. Since this is prior art, this will be not explained in
more detail in this context.
[0068] It is however important that the yoke is provided with a
parallel guiding action in a direction that is transverse to the
direction 3 of the force 2 to be measured so that the yoke 5 is
practically guided parallel to itself in two directions.
[0069] In this connection, the transverse direction 15 can be any
direction that is transverse to the line of action of the force 2
to be measured.
[0070] Expediently, the parallel guiding action of the yoke 5 as a
result of the additional parallel bending springs 12, 13, 14 is
realized in that they are also rigidly connected to the yoke 5 or
the support 10 and extend between the yoke 5 and the support
10.
[0071] The parallel guiding action of the yoke 5 in its two
movement directions can be realized therefore by an additional
arrangement of paired bending springs whose deflection plane is
positioned in the transverse direction that is to be expected.
[0072] The basic principle of the invention is therefore in this
connection to provide in the direction of the force 2 to be
measured as well as in the transverse direction 15 measuring or
bending springs that are at least arranged in pairs, respectively,
that guide the yoke in parallel in both directions according to the
principle of the double bending beam, respectively.
[0073] Since each double bending beam, as is known in the art, is
deformed in the form of an S-shape, for deflection of the yoke
under the respectively acting force a deformation work that is
correspondingly high must be performed that imparts to the entire
sensor or the entire force-sensing device 1 an excellent stiffness
in two directions. The basic principle of the invention therefore
resides in that for each of the deformation directions or load
directions to be expected a pair of double bending beams are to be
provided so that already for a minimal stroke a correspondingly
high output signal is generated while at the same time the entire
sensor has an excellent stiffness.
[0074] In order to be complete, it should however be mentioned that
it is not mandatorily required to measure the occurring transverse
forces also in the transverse direction. In this connection, it may
be sufficient to significantly increase the section modulus of the
bending springs 12, 13, 14 in the transverse direction in
comparison to the section modulus in the deformation direction of
the measuring springs provided for force measurement. Such a sensor
would therefore be suitable for taking up transverse forces that
are significantly greater than the nominal measuring forces.
[0075] The Figures, in particular FIG. 1, show thus a system of
three parallel bending springs 12, 13, 14 that are all three
deformed in parallel under the transverse load and, as a result of
this, require a correspondingly high deformation work.
[0076] In addition, the Figures show, without limiting the
invention to such geometric conditions, that the transverse
direction 15 is positioned perpendicularly to the direction 3 of
the predetermined force.
[0077] in this connection, it should be mentioned expressly that
the transverse direction 15 can be positioned at any angle to the
direction 3 of the force 2 to be measured as long as this angle is
not 180 degrees.
[0078] The respective conditions depend on the machine
requirements.
[0079] These can be predetermined in particular in regard to the
relation between the direction of gravitation and direction of the
resultant of the force to be measured upon deflection of an endless
material in such a way that between the parasitic transverse
direction as a result of dead load weight and the line of action of
the force to be measured also angles of unequal to 90 degrees are
present.
[0080] As illustrated in particular in FIGS. 1, 2, and 4, the
measuring springs 6, 7 provided for force measurement are
penetrated by slots 16, 17 that extends in the longitudinal
direction of the measuring springs 6, 7. The slot plane of the
slots 16, 17 is essentially perpendicular to the transverse
direction 15 so that in this way the measuring springs 6, 7
provided in fact for measuring the force 2 to be measured therefore
also serve for parallel guiding the yoke 5 in the transverse
direction.
[0081] In order to be complete, it should however be mentioned that
the slot planes of the slots 16, 17 must not mandatorily be
positioned perpendicularly to the transverse direction 15 but
instead other slanted directions are theoretically also
possible.
[0082] In supplementing the above, in particular FIG. 2 shows that
the yoke 5 has an annular receiving zone 18 for a rolling bearing
19.
[0083] In this way, via the rolling bearing 19 the force 2 to be
measured can also be introduced in the case of deflecting rollers,
deflecting rolls or the like into the yoke 5.
[0084] In the illustrated embodiments, the inner diameter of the
annular receiving zone 18 is however greater than the outer
diameter of a mandrel 20 penetrating the yoke 5 so that the yoke 5
has clearance for deformation of the bending springs 6, 7 while at
the same time contact between the inner diameter of the annular
receiving zone 18 and the outer circumference of the mandrel 20
ensures a reliable overload stop action.
[0085] This measure provides advantages in particular when the
support 10 is annular and is penetrated by a mandrel 20 that is
connectable rigidly to the machine frame 50. The mandrel 20 has
outside of the support 10 a head that, in turn, can be rigidly
connected to the support 10.
[0086] This measure, alone or in combination with the additional
bending springs 13, 14, 15, serves in particular for providing a
modular configuration of a sensor system, comprised of several
force-sensing devices 1 in connection with the requirement of a
floatingly supported deflection roller for strip-shaped material,
for example.
[0087] In this connection, it is proposed additionally that the
mandrel 20 can be secured infinitely variably within an angular
range of 360 degrees in any of many different rotational positions
on the machine frame 50.
[0088] For this purpose, a clamping socket 22 is provided that is
rigidly connected to the machine frame 50.
[0089] The clamping socket 22 has a fitted bore 23 that can be
combined with the outer diameter of the mandrel 20 in a slight
interference fit.
[0090] The fitted bore 23 is intercepted by a clamp bore 24 within
which a clamping jaw pair is arranged that engages the mandrel 20
on two sides.
[0091] When advancing the clamping jaw pair, wherein each clamping
jaw engages one of two opposed sides of the mandrel 20, the mandrel
20 is clamped so as to be non-rotatable, wherein additionally
during the clamping process even a minimal relative movement of the
mandrel 20 is precluded because the clamping jaw pair 25, 26
symmetrically engage the mandrel 20.
[0092] For this purpose it is proposed to load the clamping jaw
pair 25, 26 by a clamping screw 27 by means of which the two
clamping jaws 25, 26 are advanced in the direction of the mandrel
20 toward one another.
[0093] In order for the clamping screw 27 to be recessed completely
within the outer envelope of the clamping socket 22, it is proposed
additionally to provide in the first clamping jaw 25 or the second
clamping jaw 26 a through bore 29 while the other clamping jaw 26
or 25, respectively, is then provided with a threaded bore that
matches the thread of the clamping screw 27.
[0094] Providing the head 21 of the mandrel 20 with a screwed-on
flange 33 provides the advantage that by means of a counter flange
34 arranged at the end also an extension axle 35 in the sense of a
freely projecting roll bearing can be provided in accordance with
FIG. 2.
[0095] For this purpose, the extension axle 35 on its end facing
away from the counter flange 34 should have an additional counter
flange 36 on which mirror-symmetrical to the force-sensing device 1
on the machine side a further force-sensing device can be
mounted.
[0096] In this way, by means of a sensor of a modular design,
deflection rollers, measuring rollers or the like can be supported
floatingly on the machine frame 50.
[0097] Since in this respect the option of transmitting the
measuring signals by radio frequency to the exterior does not
necessarily present itself, the mandrel 20 in the longitudinal area
of the measuring springs 6, 7 should have a cable inlet opening 37
that is intercepted by a longitudinal bore 38 of the mandrel. Since
the longitudinal bore 38 of the mandrel extends at least to one end
of the mandrel 20, the measuring cables can be extended in this way
easily to the exterior.
[0098] In the embodiment according to FIG. 2, the mandrel 20 that
relates to the left force-sensing device 1 is completely penetrated
by a bore because it serves also for passing to the exterior the
measuring cables of the additional force-sensing device 1 shown in
the right portion of the illustration.
[0099] For this purpose, the extension axle 35 is also provided
with a bore across its entire length such that the axle bore 39 is
aligned with the longitudinal bore 38 of the mandrel.
[0100] However, the mandrel 20 illustrated in the right half of the
illustration does not require complete penetration by a bore
because the measuring cables expediently must be passed to the
exterior only in the direction toward the machine frame 50.
[0101] In addition to this, the mandrel 20 shown in the right
portion of the illustration according to FIG. 2 has a key engaging
surface 40 with which, when the clamping jaw pair 25, 26 is
released, the force-sensing device 1 can be aligned such that the
measuring axis coincides with the direction 3 of the force 2 to be
measured.
[0102] The effect of gravity on the deformation behavior of the
force-sensing device 1 resulting for this arrangement is
accordingly compensated via the additional bending beams 12, 13, 14
and therefore has no effect on the measuring results.
[0103] Alternatively, the FIGS. 4, 6 and 7 show however also that
the deformation of the additional bending beams 12, 13, 14 can also
be detected by sensors 111a-d. The sensors 111a-d are arranged, as
is known in the art, at locations of greatest expansion of the
bending beams, i.e., at location where they assume their S-shaped
deformation, and are appropriately provided with cables.
LIST OF REFERENCE NUMERALS
[0104] 1 force-sensing device
[0105] 2 force to be measured
[0106] 3 direction of 2
[0107] 4 location of force introduction
[0108] 5 yoke
[0109] 6 first bending spring
[0110] 6' shearing force sensor
[0111] 7 second bending spring
[0112] 8 yoke side of 6, 7; free end of 6, 7
[0113] 9 other end of 6, 7
[0114] 10 support
[0115] 11a-d measuring locations
[0116] 12 additional bending spring
[0117] 13 additional bending spring
[0118] 14 additional bending spring
[0119] 15 transverse direction
[0120] 16 longitudinal slot
[0121] 17 longitudinal slot
[0122] 18 annular receiving zone of the yoke in the rolling
bearing
[0123] 19 rolling bearing
[0124] 20 mandrel
[0125] 21 head of mandrel
[0126] 22 clamping socket
[0127] 23 fitted bore
[0128] 24 clamp bore
[0129] 25 first clamping jaw
[0130] 26 second clamping jaw
[0131] 27 clamping screw
[0132] 28 shaft of clamping screw
[0133] 29 through bore
[0134] 30 threaded bore
[0135] 31 first slanted surface
[0136] 32 second slanted surface
[0137] 33 screwed-on flange
[0138] 34 counter flange
[0139] 35 extension axle
[0140] 36 additional counter flange
[0141] 37 cable inlet opening
[0142] 38 longitudinal bore of mandrel
[0143] 39 axle bore
[0144] 40 key engaging surface
[0145] 50 machine frame
[0146] 111a-d additional measuring locations for transverse
direction 15
* * * * *